diff --git a/draw.py b/draw.py
index fb3860e..76a7ad8 100644
--- a/draw.py
+++ b/draw.py
@@ -255,7 +255,7 @@ camera_info = scene.visuals.Text(
 
 # 左上角：小球信息
 ball_info = scene.visuals.Text(
-    text="", color=(0.2, 1.0, 0.2, 1.0), font_size=28,
+    text="", color=(0.2, 1.0, 0.2, 1.0), font_size=18,
     pos=(0, 0), anchor_x="left", anchor_y="top",
     face="黑体", bold=True, parent=canvas.scene)
 
diff --git a/examples/case06/input/input.txt b/examples/case06/input/input.txt
index 6c254c5..041513b 100644
--- a/examples/case06/input/input.txt
+++ b/examples/case06/input/input.txt
@@ -19,7 +19,7 @@ save_trajectory: 0  # 0=不保留完整轨迹文件, 1=保留 trajectory.txt（
 
 # ── 计算引擎 ──────────────────────────────────
 # 可选: python, c, cpp, fortran, java
-engine: python  # 默认使用 python 引擎
+engine: fortran  # 默认使用 python 引擎
 
 # ── 盒子 ──────────────────────────────────────
 box_a: 80.0         # 立方体半边长，粒子被限制在 [-box_a, box_a]³ 内